The present invention relates to a method according to the above, which comprises the steps of:    a) creating a cut into said coating by cutting with edges of knifes substantially transversely into said coating from at least two substantially opposite directions through a substantial part of the thickness of said coating without reaching said fibre through said knife edges, and    b) displacing said element with respect to said knife edges in the longitudinal direction of said element for displacing coating material by said knives, with respect to the displacement of the element, downstream a position of said cut created by said knife edges away from this position while exposing the fibre surface thereunder,as well as an apparatus or machine for carrying out such a method.
It is for a method of this type important that said knife edges do not touch the optical fibre, which would result in unacceptable degradation of the quality of the optical fibre in the part thereof exposed by said method. As already stated, it is also crucial to remove all the coating material from the region in question of the optical fibre for obtaining a cleanest possible outer surface thereof. “Through a substantial part of the thickness” does for that sake mean as deep into said coating as necessary for being able to efficiently remove the coating by said displacement. This is material depending and it is mostly desired to not cut deeper than necessary for obtaining this. It may for instance for some coating material be sufficient to cut through only about 30% of the coating thickness. For other about 90% would be required. After the removal of coating material according to step b) in known such methods fragments of coating material still adhere to the outer surface of the fibre, and it is known to remove such fragments by use of a solvent and a cloth, which however inevitably negatively influences the quality of the optical fibre exposed therethrough.
A method of this type is disclosed in US 2002/0114609 A1, in which the optical fibre partially exposed after carrying out the step b) is immersed into a bath of a solvent, whereupon remaining fragments of coating material dissolved thereby are mechanically removed, such as by a cloth. This cloth will have a negative influence upon the quality of the optical fibre exposed.